The Science of Honey

How does it have infinite shelf life?

Honey is not exactly an ingredient you use so often. It's kind of at the backside of the cupboard sitting there to sweeten your floral tea every now and then. A few years later you finally decide to clean out your cupboard. That cupboard you would only access ever so often to find that all of your herbs and spices dried out and wilted. However, to your surprise, the honey that you had purchased so many years back still seems to be unchanged even after all that time. It looks OK, but is it really OK to eat? Heck, there was 5,000 year old honey found in Georgia, and scientist ruled it was totally safe to consume.

First and foremost, honey is sugar. It is made up of very complex chemical compounds, but at its essence, it's sugar - and sugar is hygroscopic. This means that honey is in a very dry state. So dry that bacteria or microorganisms don't have enough water to grow. Because there is such lack of moisture within honey, nothing can survive to spoil the honey, rendering honey spoil-free. 

Another reason that honey is an indefinite shelf life is because of acidity. The average pH of honey is between 3 and 4. Which is extremely acidic, and acid kills bacteria very efficiently. That's why it's quite hard to find a spoiled pickle as well. 

Then you might think, 'Aren't there other hygroscopic foods that contain almost no moisture? Why do those spoil?' For example, molasses. Molasses is a byproduct of sugar from cane, is hygroscopic and has a pH of about 5 which leans it a bit more to the acidic side. However, over time, molasses will spoil. So why does one sugar spoil and the other not?

Well the answer is because honey bees are magical...ish. Bees are essential in the production of honey and they are the reason why honey doesn't spoil, really. When bees gather the nectar from flowers, they store it inside their stomach that is separate from their normal stomach. Inside this stomach, the enzymes break down the sucrose in the nectar into glucose and fructose. When the forager bees then return back home and regurgitates, or vomits, the nectar into the house bee's mouth, the sugars break down even further. Also, when the nectar is passed from mouth to mouth, an enzyme in the stomach called glucose oxidase will mix with the nectar and break down into gluconic acid and hydrogen peroxide. After the nectar is deposited into the hive the bees start to flap their wings on the honey to drop the moisture content from about 80% to lower than 20%. With the combination of low percentage of water, highly acidic environment, and ever so slight amount of hydrogen peroxide, it makes honey's life span indefinite. 

Maybe next time you want to choose a family heirloom, you can make it a really nice jar of natural honey.